Bidirectional Allosteric Coupling between PIP 2 Binding and the Pore of the Oncochannel TRPV6

The epithelial ion channel TRPV6 plays a pivotal role in calcium homeostasis. Channel function is intricately regulated at different stages, involving the lipid phosphatidylinositol-4,5-bisphosphate (PIP ). Given that dysregulation of TRPV6 is associated with various diseases, including different ty...

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Bibliographic Details
Published inInternational journal of molecular sciences Vol. 25; no. 1
Main Authors Humer, Christina, Radiskovic, Tamara, Horváti, Kata, Lindinger, Sonja, Groschner, Klaus, Romanin, Christoph, Höglinger, Carmen
Format Journal Article
LanguageEnglish
Published Switzerland 03.01.2024
Subjects
Binding Sites
Calcium
Cytosol
Phosphatidylinositols - metabolism
TRPV Cation Channels - metabolism
calcium
TRPV6
inhibition
lipid
PIP2
cis-22a
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Summary:The epithelial ion channel TRPV6 plays a pivotal role in calcium homeostasis. Channel function is intricately regulated at different stages, involving the lipid phosphatidylinositol-4,5-bisphosphate (PIP ). Given that dysregulation of TRPV6 is associated with various diseases, including different types of cancer, there is a compelling need for its pharmacological targeting. Structural studies provide insights on how TRPV6 is affected by different inhibitors, with some binding to sites else occupied by lipids. These include the small molecule cis-22a, which, however, also binds to and thereby blocks the pore. By combining calcium imaging, electrophysiology and optogenetics, we identified residues within the pore and the lipid binding site that are relevant for regulation by cis-22a and PIP in a bidirectional manner. Yet, mutation of the cytosolic pore exit reduced inhibition by cis-22a but preserved sensitivity to PIP depletion. Our data underscore allosteric communication between the lipid binding site and the pore and vice versa for most sites along the pore.
ISSN:1422-0067